Project description:Comparison of the endogenous small RNA content of tomato leaves and fruits. Size fractionated small RNA from total RNA extracts was ligated to adapters, purified again and reverse transcribed. After PCR amplification the sample was subjected to 454 high throughput pyrosequencing. Please see www.454.com for details of the sequencing technology. Note: Raw data files were not available from 454 at the time this experiment was carried out.
Project description:Transcriptome Profiling of Tomato Fruit Development Reveals Transcription Factors Associated with Ascorbic Acid, Carotenoid and Flavonoid Biosynthesis
Project description:Tomatoes are one of the valuable sources of antioxidants such as carotenes, ascorbic acid (AsA), and phenolic compounds (flavonoids and hydroxycinnamic acid derivatives). These secondary metabolites have been proved to be beneficial for humans and animals because their involvement in the prevention of many proliferative and degenerative diseases. The aim of this work is to gain greater insights in the genetic control of phenylpropanoid accumulation in tomato fruit by using genomics-based strategies. In order to identify QTLs controlling antioxidant accumulation in tomato fruit we carried out a comparative analysis of Solanum pennellii x S. lycopersicum cv. M82 introgression lines (ILs) over three year trials in greenhouse environment. Among all, IL7-3 showed higher fruit content of total phenolics and the HPLC-UV profile revealed that chlorogenic acid mainly accounted for the higher performance of this line. To investigate in details genetic mechanisms and candidate genes controlling phenols synthesis and accumulation in IL7-3 fruit we performed a comparative transcriptomic analysis in tomato pericarp. In particular, RNA was extracted from percarp of IL7-3 and M82 parental line and hybridized on a 90k Combimatrix TomatArray 1.0. The experiment was repeated over two consecutive years. The transcriptomic approach allowed to identify 291 differentially expressed transcripts, 149 showing up-rgulation and 142 down-regulation. The ethylene signaling pathway has been involved in the modulation of the level of total phenolics in ripe fruit. In particular, an Ethilene Responsive Factor 1 (ERF1) was functionally characterized by TILLING (Targeting Local Lesion IN Genomes) approach. The mutant line expressed lower accumulation of phenolics in the fruit and additional insights on the regulation of phenolics in tomato ripe fruit were provided. Comparative microarray analysis between a tomato introgression line (IL7-3) expressing higher level of fruit total phenolics and its parental cultivar M82 (reference) was performed. In particular, samples were generated by pooling red-ripe fruit from the same plant and discarding the seeds, jelly parenchyma, columella and placenta tissues. Three plant replica were used for each line (IL7-3 and M82) and the experiment was replicated over two consecutive years.
Project description:High levels of ascorbic acid (AsA) in tomato fruits provide health benefits for humans and also play an important role in several aspects of the plant life. Although AsA metabolism has been characterized in detail, the genetic mechanisms controlling AsA accumulation in tomatoes are poorly understood. We used an introgression line (IL 12-4) containing a QTL promoting AsA accumulation in the fruit and carried out a comparative transcriptomic analysis of fruit tissue using a parental cultivar (M82) with low AsA levels as a reference. We identified 253 differentially expressed genes, indicating that AsA accumulation in IL 12-4 reflects a combination of increased metabolic flux and reduced utilization of AsA. Evidences coming from the experiment suggest that AsA accumulation in IL 12-4 fruit is mainly achieved by increasing flux through the L-galactonic acid pathway, which is driven by pectin degradation and may be triggered by ethylene.